Cannot zoom audio to maximum detail

For just one project I find myself unable to zoom in to maximum detail (i.e. to the level of individual samples).

Does anyone know what option or preference I have accidentally enabled or disabled?

At first I thought it was me getting a bit confused, but if I create a new project and insert any of the audio files of the project giving me troubles, I can again zoom in to any level of detail.


This cannot be a preferences think, preferences are global.

To me it sounds the project is corrupted somehow. Could you try to make a Back up Project? Is it the same in the backuped project?